The long-term aim of this project is to explore in greater depth the biology of the steroid-synthesizing cell. There are several areas of uncertainty as to the molecular events involving: 1) initiation, propagation, and termination of steroid synthesis, 2) intercompartmental movement of steroid precursors and intermediates, and 3) secretion of steroid products. Other areas of uncertainty involve: 1) the interaction of subcellular organelles, e.g., mitochondria, endoplasmic reticulum, Golgi apparata, microtubules, microfilaments, lipid droplets, etc., 2) cell-cell interaction or zone-zone interaction (different cells are programmed to secrete predominantly one type of steroid, i.e., glucocorticoid, mineralocorticoid, and sex steroids), 3) life-span and turnover of adrenocortical cells. Current areas of research involving: 1) identification, characterization, and physiology of noncatalytic proteins (membrane bound and/or soluble) of the adrenal cortex that interact with specific steroid ligands; 2) examination of the role of microtubules and contractile proteins in steroid synthesis; 3) identification, characterization and physiology of adrenocortical secretory proteins; 4) examination of soluble stimulatory and inhibitory factors.